1. Field of the Invention
The present general inventive concept relates to an image heating apparatus, and more particularly, to a method and apparatus to fuse an image, which can reduce a warm-up time and also can improve a fusing quality.
2. Description of the Related Art
An image heating apparatus generally includes a heating roller and a pressure roller. The image heating apparatus may pass a printing paper, formed with an image, through the heating roller and the pressure roller to fuse the image on the printing paper. Accordingly, the image heating apparatus may be used for a copying machine, a printer, a facsimile, and the like. Also, the image heating apparatus may be used to fuse character or image information on a printing paper as an image.
A main task of the image heating apparatus may be to fuse an image identical to an original image on the printing paper. Also, the image heating apparatus may reduce an initial warm-up time and power consumption.
FIG. 1 is a cross-sectional view illustrating an image heating apparatus according to a conventional art.
Referring to FIG. 1, the conventional image heating apparatus includes a pressure roller 10 and a heating roller 12. In this instance, the heating roller 12 includes a heating element such as a lamp or an electric heating coil, and may be heated up to a predetermined temperature and maintained at the temperature by using the heating element. However, since the heating roller 12 is entirely heated by a lamp 14, a comparatively greater warm-up time is required. As an example, when the entire heating roller 12 is utilized, it may take more than 30 seconds to raise the temperature of a nip up to about 160° C.
FIG. 2 is a cross-sectional view illustrating another image heating apparatus according to the conventional art.
Referring to FIG. 2, the image heating apparatus includes a pressure roller 20, a fixing roller 22, a belt 24, and a heating roller 26. In this instance, the fixing roller 22 is provided above the pressure roller 20, and the belt 24 passes through a gap between the pressure roller 20 and the fixing roller 22 via the heating roller 26. The pressure roller 20, the fixing roller 22, and the belt 24 form a nip N to fuse a toner image. A pre-fused toner image may be fused on a printing paper while passing through the nip N.
In the image heating apparatus of FIG. 2, the heating roller 26 may be formed in a comparatively smaller size and thus may be quickly heated. Accordingly, an initial warm-up time may be reduced when compared to heating the comparatively larger pressure roller 12 of the image heating apparatus of FIG. 1. As an example, when an image heating apparatus similar to the image heating apparatus of FIG. 2 utilizes a heater with a capacity of about 1.3 kW, it may take about 20 to 22 seconds to raise the image heating apparatus from room temperature up to about 160° C.
In this instance, heat is indirectly transmitted to the nip N through the belt 24 instead of direct transmission, and thus the initial warm-up time may be slow. Also, while the belt 24 is heated by the heating roller 26 and being moved to the nip N, the temperature of the belt 24 may non-uniformly change due to heat radiation, which may deteriorate a fusing quality.